Communication systems are known in which a single data channel can be used concurrently for multiple communications. One such type of system is an Integrated Services Digital Network (ISDN). With ISDN, terminal equipment can be connected to the network by two 64 Kbps channels (B-channel) and one 16 Kpbs channel (D-channel). The B-channel information is primarily circuit switched, voice, or data. The information in the D-channel is accumulated in the network to be packet switched. The D-channel information can be packet switched data or it can be control information, which is used by the network to control the switching of the B- and D-channels. Accordingly, the D-channel can be engaged in multiple concurrent communications to control multiple D-channel packet communications and the B-channel communications. Additionally, multiple user terminals may be connected to a single incoming line increasing even further the number of concurrent uses of a single D-channel.
Each active communication in a switching system is associated with a call control program and stored data describing the present state of the communication. Whenever a call-related stimulus is received, the appropriate data must be located and associated with the appropriate call control program. When a large number of D-channels is in use and each is being used for a number of communications, the total amount of stored call describing data becomes very large. Searching this data for the appropriate data and call control program becomes a difficult and time-consuming task. This is particularly troublesome in systems where the channel in which the stimulus is received does not uniquely identify the communication to which it relates. We propose an efficient method and arrangement for storing communication related data and for searching such data in systems where multiple communications may be controlled by information from a single channel.